One day, while out for a stroll, you come across your friend the desert Tortoise praying to Set, the god of desert, storms, disorder, violence, and foreigners in Egyptian mythology. You wait politely for the Tortoise to finish, and then say “Hi Tortoise, how are you?”
After exchanging pleasantries, the Tortoise makes a thoughtful expression and says “Hey, listen. If Set is the god of foreigners, who is he the god of? People foreign to where?”
“Well, I suppose it must be a question of self-identification,” you say. “Those who see themselves as foreign belong in Set’s nation.”
“Well, that’s strange,” says the Tortoise. “How can a person or group ever be foreign? You are always where you are. Nowhere you can be that isn’t where you’re meant to be.”
You think for a minute or so. “Well,” you say “once again it’s a question of self-conception. A person or group is foreign if they do not see themselves essentially as being where they are. As belonging to the nation that they are in fact in.”
“Ah.” says the Tortoise. “So Set’s nation is a nation of groups that do not conceive of themselves as within the nation that they in fact are in. Or in other words, Set’s nation is the nation of nations that do not contain themselves.”
“Exactly.” you say.
You and the Tortoise look at each other.
“So.” says the Tortoise.
“So what?” you begin to say, but then you realize. “Hey. Wait a minute. Does Set’s nation contain itself?”
The winds start to rise, and you crouch down and pull your shirt up to protect your face from the excorating dust. Almost lost in the sound of the whirling sand, you just barely hear the Tortoise shout, “Sounds like a Set paradox!”
Little known fact: Egyptian gods hate lousy math puns.